Modelling Conformational Flexibility in a Spectrally Addressable Molecular Multi-Qubit Model System

Abstract

Dipolar coupled multi-spin systems have the potential to be used as molecular qubits. Herein we report the synthesis of a molecular multi-qubit model system with three individually addressable, weakly interacting, spin $1/2$ centres of differing g-values. We use pulsed Electron Paramagnetic Resonance (EPR) techniques to characterise and separately address the individual electron spin qubits; Cu^II , Cr₇ Ni ring and a nitroxide, to determine the strength of the inter-qubit dipolar interaction. Orientation selective Relaxation-Induced Dipolar Modulation Enhancement (os-RIDME) detecting across the Cu^II spectrum revealed a strongly correlated Cu^II -Cr₇ Ni ring relationship; detecting on the nitroxide resonance measured both the nitroxide and Cu^II or nitroxide and Cr₇ Ni ring correlations, with switchability of the interaction based on differing relaxation dynamics, indicating a handle for implementing EPR-based quantum information processing (QIP) algorithms.

Keywords: Heterometallic Complexes; Molecular Magnetism; Multi-Spin; Pulsed Dipolar Spectroscopy; Quantum Information Processing.